Cutting mechanism



July 10, 1934. G. o. FROSTAD cUTTiNG MECHANISM Filed Dec. 10, 1928 Patented July 10, 1934 UNITED STATES PATENT OFFICE CUTTING MECHANISM George 0. Frostad, Milwaukee, Wis, assignor, by

mesne assignments, Cameron Machine Company, Brooklyn, N. Y., a corporation of New York Application December 10, 1928, Serial No. 324,941

19 Claims. (01. 164-60) This invention relates to cutting mechanism and more particularly to resilient cutting mechanism adapted for cutting thin material. It relates still more particularly to a resilient float- 5 ingly mounted cutting means for severing tubes of thin material such as paper or fibre. The

invention also relates to a novel knife mounting for use on tube cutting In the cutting of thin material such, for ex- ZS ample, as paper or' fibre, it is necessary that thecutting means be at all times in effective cutting relationship with the material despite changesin size of thecutter due to wear, and slight variations in the relative position of the respective parts while in operation. This is particularly true in the cutting of tubes'of thin material which are placed on a mandrel, the cutting means acting upon the outside of the tubes and severing them toward the mandrel.

20 Ordinarily in apparatus of this type the mandrel is positively rotated with the tube in place thereon and the cutting means is stationary and acts on the material as the mandrel rotates.

If the cutting means and mandrel, when in cutting relationship, can assume only one positionrelative to each other, the cutting operation cannot be satisfactorily carried out for any appreciable length of time due to wear occasioned the respective parts, and particularly the knife or cutting edge.

In order to compensate for wear in the apparatus several solutions have heretofore been proposed. One of these is the provision of a-mandrel of material relatively soft as compared with that of the cutter so that in operation the cutter not only severs the material being cut, but also grooves the mandrel. This provision has the disadvantagesthat the mandrel soon becomes badly scored and has to be replaced, and that 0 burrs are thrown up on the inside of the tube sections.

It has further been proposed to mount the cutter upon a lever pivoted at a distance from the mandrel, the cutter being resiliently pressed into cooperative relationwith the material on the mandrel by means of a spring urging the cutter pivotally into engagement therewith. Such a provision has the disadvantage that the pivotal action of the lever has the effect of vary} ing the relationship between the cutter and the material so that the cutting is not at all times uniform.. Furthermore, thesprings are exposed and frequently become damaged or out of proper adjustment. 5

'55 The problem assumes greater importance when a plurality of cutters arranged along a material supporting means such as a mandrel is used for.

simultaneously cutting the material. Under such circumstances it is necessary that all of the cutters maintain their proper cooperative relationship with the material and its support and exert a substantially constantand uniform pressure thereon despite unequal wear in the respective cutters. The solution first proposed,

that of using a relatively soft mandrel, is quite unsuited for use when a plurality of cutters is used. In some places the mandrel may be badly grooved; while in other places the cutters'mayv 'not even completely sever the material. When cutters mounted upon pivotedlevers and spring actuated into contact with the material being out are used, if there is any difference in the adiustment of the respective cutters or of the, tension of the respective springs, the result will be equally unsatisfactory.

I provide a cutting mechanism adapted to overcome the disadvantages above noted and to satisfactorily and uniformly sever thin material irrespective of wear in the cutting mechanism. I provide for the use of hardened cutters against a hardened material supporting means in such a manner that each of the respective cutters in a series will at all times exert substantially the same effective cutting pressure on the material,

even though one or more of the cutters may be substantially more greatly worn than others. I

provide for resilient adjustment within the cutters themselves and do not rely upon external springs or pivoted levers. Due to the fact that a hardened cutter may be used against a hardened mandrel, no burrs will be thrown up on the cut portions of material and the mandrel will ,not become scored in a relatively short time, as

is the case when a soft mandrel is used.

I provide cutting mechanism comprising a ro- Figure 1 is an elevational view of cutting mechanism Figure 2 is a central vertical cross section through the cutting mechanism shown in Figure 1,

Figure 3 is an end view of a tube cutting apparatus, and

Figure 4 is a detail view to enlarged scale of a portion of the mechanism shown in Figure 3. 10 Fig. 5 is a fragmentary top plan view of Fig. 4, showing a plurality of cutters mounted onra common shaft. Referring more particularly to the drawing and to Figures 1 and 2 thereof, reference numeral 2 designates generally a bushing or collar having at one axial extremity a radial flange 3 provided with circumferentially spaced inwardly extend- V ing slots 4. The bushing 2 bass bearing portion 5 of less diameter than the flange 3 and at 2 the extremity of the bearing portion opposite the flange 3 is provided with a slightly outwardly extending radial ring 6. At the extremity of thebushing adjacent the ring lithe bushing is threaded as at 'l.

0f suillciently larger diameter than the ring 6 to permit of its passage thereover, is a. frame or cage 8 disposed about the bearing portion 5 of the bushing. The frame 8 is provided with cir- 'cumferentially spaced radially extending openings 9,.each adapted to contain a compressed spiral spring 10. Of sumciently greater diameter than the frame 8 to permit of its reception thereover, is a flat hoop 11. The hoop 11 serves as a stop for the outer extremities of the respective springs 10. Its width'is substantially the same as the width of the frame 8.

The openings 9 extend through the innerperiphery of the frame 8 so that the inner ex' tremities of the respective springs are free to 40' contact with the bearing portion -5 of the bushing 2. By reason of this provision the frame is resiliently urged by the springs 10 away from the bushing 2 an equal amount in all directions, duetothe fact thatallofthe springsare ofthe 48- same size and have the same compressive strength. The frame thus in effect floats upon the bushing.- 5

Disposed between the flange 3 and the frame is a hollow circular hiife 12 whose internal diameter is substantially the same as the internal diameter of the frame 8 and whom external diameter is substantially greater than the external diameter-of the flange 3. The knife 12 is provided with a peripheral cutting edge 13. The frame 55- 8 and the knife 12 have corresponding threaded openings 14 through which pass screws 15. The knife is thus rigidly and permanently connected with the frame. a

Theheadsloofthescrewslfiareattheright ;O0-'oftheknife,yiewingl"igure2,andarecontained withintheslots'4oftheflange3, asshown in.

Figure 1.'Tl 1eslots4aremateriallylargerin size than the screw heads 16,-thus allowing rel ative motion to a certain extent between the cut- 1 ll; ting unit comprising the frame 8, the springs 10,

hehoop 11 and the knife 12, and the bushing 2. Such cutting imit is resiliently movable'ra dially of the bushing and, as above described, movable to a certain extent circumferentially '0 thereof, but, as will be presently described, is'

restrained from movement axially with /thereto'.

Cooperating with the through thescrewthreads'lisanutl'lhavingcooperating threads is and having an annular inwardly probushing.

Jecting portion 19 extendingover the ring 6 and into close proximity with the frame 8. A set screw 20 is provided for maintaining the nut in place on the bushing. Suitable for the reception of a capstan wrench; (not shown) may also be provided in the nut. The cutting unit is thus restrained from movement axially of the By reason of the screw heads 18 lying within the slots 4 in the bushing flange. rotation of the bushing causes positive rotation of the cuting unit comprising, as above stated. the frame 8, the springs 10, the hoop hand the knife 12. The cutting unit is positively guided axially of the bushing by the flange 3 and the annular portion 19 of the nut 1'7. The cutting unit is, however, floatingly mounted radially of the bushing by reason of the provision of the springs 10. It is capable. of radial translatory movement. upon compression of any of the springs toward the axis ofthe bushing. Advantages. of thisprovision will be presently described.

InFigureZiofthe drawingthecuttingmechanismisshownasappliedtoatubecuttingmachine havinga hardened mandrel 21 carried by adrivenshaft22. Atube23of materialtobecut is placed over the mandrel and the shaft-22 rotated, whereupon the cutting mechanism is brought into cutting relationship therewith. The detailed mechanism of the tube cutter forms no part'of the invention herein claimed, and is fully described and claimed i my co-pendingtapplication Serial No. 324,948 flied r 10, 1228. It is sufficient for present purposes that the mandrel 21 having the tube 23 thereon is rotatable to permit of cutting the tube.

Reference numeral 24 designates generally the frame of the tube cutter. The frame is provided with extensions 25 carrying cylindrically bored buses 26. Passing through each of the bosses28isascrew2'ltowhichatoneextremity isattachedabcaring28. BachscrewflismainatSOandtothefrImeatMFDoInwardpressme-uponthefootrestfl ofthetreadle depresses the treadle againstthe action of the spring 88,

' P rt 50.

is a clamping plate 48 with the-rear face of which construction. Both the knife 12 and the mandrel the rounded extremity 46 of the screw 45 contacts. The frame is attached to the tubular member at a dovetail projection 31 byplacing the slot 43 over the projection 31,and then tightening the screw 45 to bring the clamping plate 48 into clamping engagement with the projection 31. The frame 42 is thus rigidly connected to the control mechanism and partakes of its movement upon actuation of the control rod 34.

Pivoted to the frame 42 at 49 is a cutter sup- Such support has an extension 51 disposed between two opposite faces of the frame 42. Through one of these faces is threaded an adjustable stop screw 52 having a rounded extremity 53.

The stop screw 52 is provided with a lock nut 54 to maintain it in a desired position. OpDOsite the stop screw 52 the frame 42 is slotted as at 55. Through the slotted portion of the frame is a circular hole 56 into which is threaded an adjusting screw 57. Disposed within the hole 56 and abutting at one end against the adjusting screw 57 and at the other end' against. the extension 51 of the'cutter support is a coil spring 58. Pins 59 and 60 are provided respectively in the extension 51 and the adjusting screw 5'l-for maintaining the coil spring in proper relationship therewith.-

A locking screw 61 .is provided which passes through the slot 55 near its outer extremity and compresses the portions of the frame 42 on opposite sides thereof so as to lock the adjusting j screw 57 in a desired position. By means of the mechanism described, the cutter support 50 is urged to inove in a clockwise direction around its pivotal mounting 49 by the coilspring 58, but such movement is limited by the stop screw 52. The cutter support 50 may be'moved in a'counter clockwise direction about its pivot against the action of the spring 58. The bushing 2 is journalled in the cutter support 50 at 62.

Depression of the treadle 36 causes,-as above described, clockwise rotation of the member 30 which carries the frame 42 and the cutting mechanism. Such movement of the member 30 is effective for bringing the cutting mechanism into cutting relationship with the tube 23 on the hardened mandrel 21.

In the described embodimentwof the invention a doubleresilient action is obtained. The floating cutting unit itself is yieldable under pressure -useful when a non-floating or rigid cutter is used. The two are shown in combination in order to indicate the utmost resiliency which may be obtained.

When the cutting mechanism is brought into cutting relationship with the tube, a pressure is exerted upon the hardened mandrel 21 which causes compression of the respective coil springs 10 -as the cutting mechanism-rotates, due to the influence .of the rotating mandrel and tube. The cutting unit itself may therefore actually be rotated about an axis eccentric to the axis of the bushing 2. A substantially constant pressure is' brought to bear upon the mandrel at all times. When a plurality of cutters is used on the same machine and one or more of them happen to be worn to a greater extent than others, this is compensated for by the yieldable and floating 21 being hardened, the mandrel will not be badly grooved and burrs will not be thrown up at the the necessary compensation between respective cutters which in all ordinary circumstances is suflicient.

An advantage of having the sole resilient means in the cutting mechanism is that when the cutter support is restrained from pivotal movement the direction of the pressure or force exerted by a knife against the mandrel is at all times substantially the same, whereas if the cutting mechanism is carried on a pivotally movable lever, such as the cutter support 50, the relationship between the cutting mechanism and the mandrel may continually vary. This results in uniform cutting of the tubes.

If desired the respective cutters may be mounted upon a common shaft extending generally parallel to the axis of the mandrel and passing through each of the respective bushings. Such an arrangement is shown in Fig. 5 where a plurality of cutters 2 are mounted on a common shaft 62. The different arrangements of the respective parts which might be resorted to within the scope of the invention is well nigh limitless, and, although I have shown anddescribed 'a present preferred embodiment of the invention, I wish it distinctly understood that the same 'is not limited thereto but may be otherwise. embodied within the scope of the following claims.

I claim:

1. Cutting mechanism, comprisinga shaft and a generally circular and rigid knife resiliently carried thereby tobe rotatable thereabout both concentrically and eccentrically with respect thereto.

2. Cutting mechanism, comprising a shaft, cutting means thereon,-a series of coil springs disposed aboutthe shaft and abutting at their outward extremities against the cutting means to resiliently support the same, and guide means for guiding the cutting means generally axially of the shaft.

3. Cutting mechanism, comprising supporting means for material to be cut, and rotatable cutting means-adapted to move relatively to the supporting means, the cutting means being rigid but floatingly and resiliently mounted about the axis of rotation whereby to at all times exert a cutting pressure on the material while accommodating itself to changes in size occasioned by wear.

4. Cutting mechanism, comprising a; collar, a hollow circular knife having an internal diameter greater than the external diameter of a portion of the collar about which the knife is disposed, and resilient means between the knife and collar.

5. Cutting mechanism, comprising a collar having radial flanges, and cutting means resiliently and floatingly mounted on the collar between the flanges.

6. Cutting mechanism, comprising a collar, an annular frame surrounding the collar, spring means between the collar and frame for resiliently supporting the latter upon the former, and a knife connected to the frame.

8. Cutting mechanism, comprising support-- ing means for material to be cut and a plurality of rotatable cutters disposed therealong, such cut-' ters being rigid but floatingly mounted about the axis of rotation-whereby to compensate for un- 7 equal wear.

9. Cutting mechanism, comprising a hardened supporting means for thin material to be cut and a hardened rotatable cutting means cooperating therewith for cutting the material, the cutting means being rigid but floatingly mounted about the axis of rotation whereby to exert a -substantially uniform cutting pressure in spite of wear on the parts.

l0. Slitting means including: a backing roll, a

freely rotatable supporting member, and a rigid score-cut slitter, to engage the backing roll, so

. cumferentially.

mounted on the supporting member as to be capable, in response to pressure exerted by it against the backing roll, of yielding movement at any point circumferentially.

11. A slitting means including: a supporting member, and a circular and rigid slitter. so mounted on the supporting member as to beporting member and the slitter.

capable of aradial movement at any point cir- 12. A slitting, means. including: a freely rotatable'supporting member, and a circular and rigid slitter' mounted to rotate with-the sup.- porting member and capable of a radial movement with respect thereto at any point circum-' ferentially.

13 .;A slitting means including: a supporting' member, an annular and resilient mounting on the supporting member, and a circular and rigid slitter carried by the resilient mounting.

14. A slitting means including: a freely rotatablesupporting member, an annular and resilient mounting on the supporting member and-- rotatable therewith, and a circular and rigid from the backing roll, a rigid score-cut slitter' mounted on the supporting member, and resilient means interposed between the supporting member and the slitter.

17. Slitting means including: a backing roll.

a freely rotatable supporting member, a rigid score-cut slitter, to engage the backing roll, mountkd to. rotate with the supporting member, and resilient means interposed between the supporting member and the slitter.

18. Slitting means including: a backing ro a freely rotatable supporting member, means to move the supporting member J oward and away from the backing roll, a rigid score-cut slitter mounted to rotate with the supporting member, and resilient means interposed between the sup- 19. Slitting means including: a backing roll, a supporting member, a plurality of rigid scorecut slitters, to engage the backing roll, mounted coaxially on the supporting member, and means to admit of'individual yielding movement of said slitters one independently of another in a directionradial with respect to said supporting member and at any point circumferentially thereof when said slitters are pressed against the backing roll.

GEORGE O; FROS'IAD. 

